In present iron-nickel batteries, the nickel electrode can contain an electrode paste prepared from an aqueous slurry of: (1) NiCO.sub.3.2Ni(OH).sub.2.4H.sub.2 O or 2NiCO.sub.3.3Ni(OH).sub.2.4H.sub.2 O, i.e., hydrated mixtures of nickelous carbonate.nickelous hydroxide, and (2) CoCO.sub.3 and/or Co(OH).sub.2. This slurry must be oxidized with hypochlorite ion, hypobromite ion, or the like, prior to drying and application to the plaque, as taught by Jackovitz et al., in U.S. Pat. No. 3,928,068. Such plaques require from 5 to 15 charge-discharge "formation" cycles to achieve maximum electrochemical output.
While the output of this paste approaches about 0.24 amp-hr/gram, close to the theoretical output of about 0.26 amp-hr/gram, it would be highly advantageous if outputs even closer to theoretical could be realized. In addition, the required oxidation of the hydrated, hydroxy containing nickel material adds to the cost of the final electrode plate. Finally, the hydrated, hydroxy containing nickel material is itself now expensive and difficult to obtain commercially, and is subject to significant expansion after hundreds of cycles. There has been a long felt need than, for a less expensive nickel electrode paste of higher output, requiring less "formation" pre-conditioning, which would also show little expansion during its useful lifetime.